1. Field of the Invention
The present invention relates to a technique for improving dynamic characteristics of an image projected by, for example, a projector.
2. Description of the Related Art
A projected video upon projecting a video by a liquid crystal projector suffers problems related to low contrast and low dynamic characteristics due to floating blacks. Deterioration of dynamic characteristics are caused by a long time period required for an orientation change of liquid crystal elements which determine the transmission amount of light when a luminance level of a pixel in a video signal changes; that is, a long time period is required until the luminance level of projected light becomes stable.
According to Japanese Patent Laid-Open No. 2009-116098, two light modulation systems are provided, and light coming from a light source undergoes double light modulations, so as to suppress floating blacks and to realize high contrast. However, even this system cannot improve dynamic characteristics. According to Japanese Patent Laid-Open No. 8-171098, for example, a general normally white liquid crystal element has characteristics in which a luminance change from white to black is faster than a change between intermediate tones.
In either case, even with the related arts, the dynamic characteristics of a video image projected by a liquid crystal projector remain low.